Thread (12 messages) 12 messages, 2 authors, 2025-01-07

Re: [PATCH v6 0/7] can: m_can: Add am62 wakeup support

From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: 2024-12-22 16:53:40
Also in: linux-arm-kernel, linux-can, linux-devicetree, lkml

On 19.12.2024 20:57:51, Markus Schneider-Pargmann wrote:
Hi,

Series
------
am62, am62a and am62p support Partial-IO, a poweroff SoC state with a
few pin groups being active for wakeup.

To support mcu_mcan0 and mcu_mcan1 wakeup for the mentioned SoCs, the
series introduces a notion of wake-on-lan for m_can. If the user decides
to enable wake-on-lan for a m_can device, the device is set to wakeup
enabled. A 'wakeup' pinctrl state is selected to enable wakeup flags for
the relevant pins. If wake-on-lan is disabled the default pinctrl is
selected.

After feedback from Nishanth and Krzysztof, I moved to a wakeup-source
property that can be a list of powerstates in which the device is wakeup
capable. This describes special cases like Partial-IO where the device
is powered off but pins can be sensible to changes and trigger a wakeup.

It is based on v6.13-rc1.

Partial-IO
----------
This series is part of a bigger topic to support Partial-IO on am62,
am62a and am62p. Partial-IO is a poweroff state in which some pins are
able to wakeup the SoC. In detail MCU m_can and two serial port pins can
trigger the wakeup.
A documentation can also be found in section 6.2.4 in the TRM:
  https://www.ti.com/lit/pdf/spruiv7

This other series is relevant for the support of Partial-IO:

 - firmware: ti_sci: Partial-IO support
   https://gitlab.baylibre.com/msp8/linux/-/tree/topic/am62-partialio/v6.13?ref_type=heads

Testing
-------
A test branch is available here that includes all patches required to
test Partial-IO:

https://gitlab.baylibre.com/msp8/linux/-/tree/integration/am62-partialio/v6.13?ref_type=heads

After enabling Wake-on-LAN the system can be powered off and will enter
the Partial-IO state in which it can be woken up by activity on the
specific pins:
    ethtool -s can0 wol p
    ethtool -s can1 wol p
    poweroff

I tested these patches on am62-lp-sk.

Best,
Markus

Previous versions:
 v1: https://lore.kernel.org/lkml/20240523075347.1282395-1-msp@baylibre.com/ (local)
 v2: https://lore.kernel.org/lkml/20240729074135.3850634-1-msp@baylibre.com/ (local)
 v3: https://lore.kernel.org/lkml/20241011-topic-mcan-wakeup-source-v6-12-v3-0-9752c714ad12@baylibre.com (local)
 v4: https://lore.kernel.org/r/20241015-topic-mcan-wakeup-source-v6-12-v4-0-fdac1d1e7aa6@baylibre.com (local)
 v5: https://lore.kernel.org/r/20241028-topic-mcan-wakeup-source-v6-12-v5-0-33edc0aba629@baylibre.com (local)

Changes in v6:
 - Rebased to v6.13-rc1
 - After feedback of the other Partial-IO series, I updated this series
   and removed all use of regulator-related patches.
 - wakeup-source is now not only a boolean property but can also be a
   list of power states in which the device is wakeup capable.

Changes in v5:
 - Make the check of wol options nicer to read

Changes in v4:
 - Remove leftover testing code that always returned -EIO in a specific
 - Redesign pincontrol setup to be easier understandable and less nested
 - Fix missing parantheses around wol_enable expression
 - Remove | from binding description

Changes in v3:
 - Rebase to v6.12-rc1
 - Change 'wakeup-source' to only 'true'
 - Simplify m_can_set_wol by returning early on error
 - Add vio-suuply binding and handling of this optional property.
   vio-supply is used to reflect the SoC architecture and which power
   line powers the m_can unit. This is important as some units are
   powered in special low power modes.

Changes in v2:
 - Rebase to v6.11-rc1
 - Squash these two patches for the binding into one:
   dt-bindings: can: m_can: Add wakeup-source property
   dt-bindings: can: m_can: Add wakeup pinctrl state
 - Add error handling to multiple patches of the m_can driver
 - Add error handling in m_can_class_allocate_dev(). This also required
   to add a new patch to return error pointers from
   m_can_class_allocate_dev().

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
LGTM, next we need Krzysztof Kozlowski's ACK for DT bindings update. The
dts changes (patches 5...7) will not go via the CAN tree but AFAICS via
Vignesh Raghavendra.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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